Expanding device for tubular envelopes



Aug. '8, 1939.

} A. J OSEPH EXPANDING DEVICE FOR TUBULAR ENVELOPES Filed May 14, 1937 jeam wafer jfwewfor Patented Aug. 8, 1939 EXPANDING DEVICE FOR TUBULAR ENVELOPES Alex Joseph, Amsterdam, Netherlands Application May 14, 1937, Serial No. 142,655 In the Netherlands May 14, 1936 1 Claim.

My invention relates to the manufacture of envelopes designed to protect rod-shaped articles such as for instance slate-pencils, leads, color pencils, etc., against breakage. It has particular reference to tubular envelopes made of some flexible material such as for instance Celluloid, which can be easily cut through when pointing the pencil or the like.

In order to firmly seat such envelope on the article to be protected, the inner diameter of the envelope must be slightly larger than the outer diameter of the article. To this end Celluloid tubes have already been expanded by treating them with hot water, whereupon the pencil or the like has been introduced into the envelope, and this latter shrunk onto the pencil by quenching it with cold water.

It has further been suggested to impart to the envelope a larger diameter by drawing it in heated condition onto a mandrel and to thereafter cool the envelope, whereuponthe article is introduced and the clearance between the article and the envelope filled with a binder such as plaster of Paris.

It is an object of my invention to render the use of such binder superfluous and to produce tubular envelopes made of Celluloid or the like on a quantity basis in a particularly simple and efiicient manner. To this end the tubes, heated to a suitable temperature, are slowly drawn over a mandrel of increasing diameter, whereby the tubes are imparted an inner diameter slightly exceeding the outer diameter of the pencil or the like. The expansion of the tube is rendered permanent by cooling. A length of tube equalling that of the article to be covered is then cut off and the article introduced, whereupon the tube is heated together with the article, for instance in boiling Water, whereupon the Celluloid tube will shrink and firmly embrace the pencil or the like,

Probably the expansion of the tube sets up strains in the tube wall, which are fixed by the immediate cooling down, so that the diameter of the tube remains constant for some time- As soon however as the tube thus treated is heated in hot water or in some other suitable manner, the strains existing in the material will cause the tube to shrink, whereby the tube is firmly fixed on the pencil or other article introduced into it without the use of any binder.

In the drawing affixed to this specification and forming part thereof a device for treating Celluloid and other tubular envelopes to expand it and to fix their expanded condition, as intended according to this invention, is illustrated diagrammatically by way of example in axial section,

Referring to the drawing, I is a mandrel of a diameter such as to exactly fit in the Celluloid or other tube before it is expanded. 2 is a conical shoulder formed on the mandrel, the diameter of which increases from this point on to considerably exceed the part I. 3 is a steam box with an inlet 5' and outlet 5 and with central apertures 6 formed in opposite walls, while I are paclc'ngs, for instance rubber packings serving to prevent the escape or" steam. The mandrel l extends through the apertures 6 with the conical shoulder 2 surrounded by the steam box, the clearance between the mandrel and the packings being so chosen, that a Celluloid tube can pass through.

8 is a cooling box surrounding the expanded part of the tube and adjoining the steam box. The box 8 is fitted with an intake and exhaust for cold water and with packings similar as the steam box 3.

9 are feed rollers near the first section of the mandrel l and Hi, I!) are similar rollers adjoining the larger section, I! is a Celluloid tube drawn over the mandrel and I2 is the expanded section of this tube.

The Celluloid tube l l is drawn, in the direction of the arrow, onto the tube l by the feed rollers 9 and on entering the steam box 3 is softened by the hot steam to the extent of becoming expansible, so that the feed rollers It can pull it onto the larger section of the mandrel and through the cold water box 8, where the expansion of the tube is rendered permanent for some time. In this manner the diameter of the tube can be increased in such manner as to enable it to be easily mounted on the pencil or the article to be enveloped. The pencil with the tubular envelope mounted thereon is then placed in boiling water or the like, whereby the envelope is caused to shrink and to firmly embrace the pencil or the like, which is thus efficiently protected.

Obviously the means for heating and cooling the material forming the envelope may be varied in accordance with the requirements of each individual case.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

I claim:

Expanding device for tubular envelopes consisting of a cellulose compound such as Celluloid, comprising in combination, a mandrel in two sections differing in diameter with a conical shoulder connecting the two sections, a heating chamber surrounding the conical shoulder of the mandrel, a cooling chamber surrounding a portion of the larger section of the mandrel and means for drawingthe envelope to be expanded axially over the mandrel and through said chambers.

ALEX JOSEPH. 

